The CV3840 is a TR (transmit/receive) cell for use with X-Band radar systems. The TR cell is essentially a cold cathode device but a primer potential is applied to keep the gas within gust below ionisation. When a transmit pulse appears on the common waveguide the cell ionises and shorts out the receiver waveguide thus protecting the sensitive front end from the power of the magnetron. The cell has to de-ionise quickly after the transmit pulse so that the receiver may pick-up the return echo.
The KB/RB identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the RB identifies the maker as Ferranti, Dundee.
The cell is located within WG16 and the primer voltage connects to the screw top cap.
The sharp point concentrates the potential and ensures maximum ionisation speed across the gap. The knurled wheel is calibrated for tuning and the square section allows the attachment of a rod to bring the adjustment to the front panel.
The tuning wheel.
The thin glass tube envelope is 15 mm in diameter, and including the base is 95 mm tall.
